A Magnetic Attraction

[peregrinvs]

I had the good fortune last week to spot a miss-listed WWI Brodie helmet shell on eBay with a bargain buy-it-now price and I quickly snapped it up. I had assumed from the chinstrap bale shapes it was an ordinary MkI that had lost it's rim. However, look what happened when I tried the magnet test...

 

Edited 3 April , 2017 by peregrinvs

[johnboy]

What's the magnet test?

[peregrinvs]

Some more pictures. It was very grubby and faded, but a wash and a rub down with oil has brought some of the colour back. It has smooth green paint inside the crown, but on the outside and around the rim on the inside, someone has crudely brushed on a thick coat of dark blue. (Sadly some wretch has also later given it a couple of random squirts of white spray paint on one side )

 

So what do I have here? Is it an early War Office Pattern later refitted with MkI chinstrap bales? There's no obvious sign it ever had a rim, but the thick blue paint makes it difficult to tell. It has also largely obliterated the markings, although I think I can just about make out an 'S' and a '17'. Also, is the blue paint likely to be military? It looks old, but I've no idea if it is pre-1918.

 

All suggestions / input / advice / etc. gratefully accepted.

 

[MikB]

Why should it not be magnetic? Army instructions for magnetic compasses said they'd be affected within specific distances of various battlefield objects, and even a tin hat counted for a yard or two IIRC.

Edited 3 April , 2017 by MikB
typo

[JMB1943]

I asked somebody about this on another part of the forum (or another forum ?) and was told that the early helmets did indeed adversely affect compasses.  This effect was removed by including a smallish amount (~10-15% ?) of manganese in the metal.

Regards,

JMB

 

Edited 3 April , 2017 by JMB1943
Typo

[seaJane]

On 4/3/2017 at 21:12, JMB1943 said:

the early helmets did indeed adversely affect compasses

The Admiralty also had trouble:-
Admiralty Weekly Orders, 1911
117. Men wearing Trusses not to act as Helmsmen or Quartermasters
A case having arisen in which a ship’s compass was deflected from 3◦ to 7◦ by the proximity of a person wearing a truss which had become highly magnetised, it has been decided that no man who has to wear a truss is to take the duty of helmsman or quartermaster.

[Chasemuseum]

8 hours ago, MikB said:

Why should it not be magnetic? Army instructions for magnetic compasses said they'd be affected within specific distances of various battlefield objects, and even a tin hat counted for a yard or two IIRC.

A basic feature of the Brodie helmet was the use of "Hadfield's Alloy Steel", a high manganese, heat treatable alloy steel. Hadfields alloy had very good drawing properties allowing the shell to be cold drawn in a single pressing, then heat treated. All Brodies other than decorative private purchase aluminium helmets for parade use should be attracted by magnets.

 

To get a really good understanding of the problems of helmet design and manufacture in WW1 read: Basford Dean: "Helmets and body armor in modern warfare" Originally printed in 1919, covering the development of the steel helmet for the USA army, it was reprinted after WW2 with some updates, by C. J Puglise of New York in 1977. 

Cheers

Ross

[Tony N]

14 minutes ago, Chasemuseum said:

 

To get a really good understanding of the problems of helmet design and manufacture in WW1 read: Basford Dean: "Helmets and body armor in modern warfare" Originally printed in 1919, covering the development of the steel helmet for the USA army, it was reprinted after WW2 with some updates, by C. J Puglise of New York in 1977. 

Cheers

Ross

Very hard to find but luckily, and for anyone who isn't aware, it's available online https://archive.org/details/helmetsbodyarmor00deanuoft

 

Ross, I didn't know about the reprint so thanks for the tip. There are plenty on Abe Books so not as hard to find as I thought.

 

Tony

[MikB]

1 hour ago, Chasemuseum said:

A basic feature of the Brodie helmet was the use of "Hadfield's Alloy Steel", a high manganese, heat treatable alloy steel. Hadfields alloy had very good drawing properties allowing the shell to be cold drawn in a single pressing, then heat treated. All Brodies other than decorative private purchase aluminium helmets for parade use should be attracted by magnets.

 

Cheers

Ross

 

This is quite confusing if Hadfield's ~15% manganese alloy was supposed to be non-magnetic as many sources say it is. Why would the compass instructions bother with tin hats if it was?

[CGM]

Type A Brodies were mild steel and magnetic.

Type B Brodies (Hadfield's steel) were non-magnetic.

 

1915

The first Brodie design, the 'Type A', had a 'raw' or 'un-edged' brim of about 1 3/4-2in wide, and was also made of mild steel. Type A Brodies were in production for just a few weeks, and only a limited run of 4,400 units was made, destined for the Allied Front Line.

 

Initial production was halted when distinguished metallurgist Sir Robert Hadfield (1858-1940) stepped in with a proposal to alter the method of manufacture slightly. This next version was called the 'Type B', and its production began in October 1915.

The Type B shell used mangalloy, or Hadfield's steel as it came to be known – a manganese steel alloy that Hadfield discovered in 1882. The 10-15 per cent manganese content contained about 1 per cent carbon, making it a non-magnetic steel with higher impact strength and improved abrasion resistance when the correct work-hardened state was achieved.

 

Is yours a Type A, Peregrinvs ?

CGM

 

E&T Engineering and Technology Magazine

vol 9, issue 6

https://eandt.theiet.org/content/articles/2014/06/ww1-combat-helmet-technology-the-brodie-steel-helmet/

WW1: Combat helmet technology - the Brodie steel helmet
16 June 2014 By Dan Shadrake

Edited 4 April , 2017 by CGM
LINK ADDED

[CGM]

I would be interested to know when production of rimmed Brodies started. I believe in 1916, but what month?

 

CGM

[peregrinvs]

33 minutes ago, CGM said:

 

Is yours a Type A, Peregrinvs ?

 

Well that's what I'd dearly like to know. There's no ambiguity that it is made of magnetic steel, but it also clearly appears to have the later type chinstrap bales.

 

It measures about 1 3/4in at the sides and about 1 1/4in at the front and back. The latter look noticeably shorter than the ordinary MkI in my other thread.

Edited 4 April , 2017 by peregrinvs

[Chasemuseum]

Mike,

Magnets are attracted to most common steels. The stainless steels (chromium-nickel) alloys are non-magnetic. The problem with compasses is how close is the compass to the piece of ordinary steel ?  Generally 15 to 20cm clearance is all that is required.

 

The next problem is that ordinary steels can be made into low grade magnets through cold work.  This is a much greater problem for a compass, with a much greater safe clearance required. I would expect the real problem of a naval helmsman wearing a steel strip reinforced truss. There is a magnetic field around all electrical wiring while current is flowing - again this is a serious problem for a compass.

 

Unfortunately I have seen army prismatic compasses corrupted by storage where strong magnetic fields were present. We only found out after a navex went bad and checked the calibration of the compasses.

Cheers

Ross

[CGM]

1 hour ago, peregrinvs said:

Well that's what I'd dearly like to know. There's no ambiguity that it is made of magnetic steel, but it also clearly appears to have the later type chinstrap bales.

 

It measures about 1 3/4in at the sides and about 1 1/4in at the front and back. The latter look noticeably shorter than the ordinary MkI in my other thread.

 

I understand. 

[Michael Haselgrove]

Dear All,

 

The Type "B" Brodie in my collection is definitely magnetic steel.  All other Brodie shells including the Examples of the "War Office Pattern" are non-magnetic but the rims, where fitted, are magnetic.  My understanding is that the requirement was that helmets should pass the ballistic test, etc. and I can trace no War Department requirement that helmet shells should be made from magnetic or non-magnetic steel. However, if anyone has information in this respect I shall be very pleased to hear. 

 

My opinion, for which I have no authority, is that the magnetic shells encountered were manufactured from steel supplied by the U.S.A.   This makes sense as the American Model 1917 helmets in my collection are all magnetic.

 

Peregrinvs,

 

The "Type A" helmet measured 295mm from side to side and 317mm from front to rear.  The brim measured 40mm at front and rear and 50mm at each side.  The Type "B" measured 262mm from side to side and 288mm from front to rear.  The brim was 35mm on one side and 32mm on the other and 25mm at the front and 29mm at the rear.  The measurements given are not necessarily to be relied upon as they varied by up to 3mm on different examples particularly on the Type "B" and it goes without saying that not many examples were available.  

 

Regards,

 

Michael.

[peregrinvs]

(Gets out ruler)

 

Give or take a couple of MM, it measures 302mm front to back and 292mm side to side. I'll insert the caveat though that the 'front' (opposite end to where I think the markings are) looks to be a slightly less even curve than the 'back', although I don't think it makes much more than 1mm or so difference.

[trajan]

14 hours ago, seaJane said:

The Admiralty also had trouble:-
Admiralty Weekly Orders, 1911
117. Men wearing Trusses not to act as Helmsmen or Quartermasters
A case having arisen in which a ship’s compass was deflected from 3◦ to 7◦ by the proximity of a person wearing a truss which had become highly magnetised, it has been decided that no man who has to wear a truss is to take the duty of helmsman or quartermaster.

 

 Incidentally, a mate of mine, ex-Dutch army regular, found himself in trouble, as when acting about (when new to the game) he decided to emulate those WW2 films in which USA soldiers boiled water in their helmets...  

[peregrinvs]

A little addendum whilst we ponder whether this is a 'Type A' War Office Pattern helmet.

 

Coincidentally, on the same day I took delivery of this late 1930's Civil Defence helmet which was another fortunate eBay spot. (Not that I waste a lot of time on eBay of course...) Those of you who know your British helmets will know what it is and what the Great War connection is. 

 

[trenchtrotter]

Given the. Umber of magnetic ones that are out there there must be more than the 4000. I'm with Micheal.

[JMB1943]

Given that the stamp of HS 4xx possibly indicates the particular batch of Hatfield steel that was used, is it magnetic or not?

Regards,

JMB

[peregrinvs]

Trying a different tack: does anyone have or know of a British made MkI that is made of magnetic steel?

[peregrinvs]

The plot thickens...

 

I decided to go for broke with identifying it and removed the blue paint off the top of the stamped markings. Not only did the stripper take the blue off, it also went through the green to reveal... khaki.

 

Having looked more carefully, you can see a couple of patches of khaki by the suspension rivet where the green paint didn't go over it.

 

Edited 5 April , 2017 by peregrinvs

[peregrinvs]

I note though that there's still no obvious sign of a missing rim as the khaki paint goes more or less to the edge. The missing rim was obvious on the rusted MkI I cleaned up in the other thread. Did they repaint MkI's without replacing missing rims? Also, try hard as I might I can't read the markings as anything other than 'S 17'. Who are 'S'?

 

I think on balance of probability this isn't a 'Type A', but this helmet continues to puzzle me...

Edited 5 April , 2017 by peregrinvs

[Guest]

On 4/4/2017 at 06:56, Michael Haselgrove said:

Dear All,

 

The Type "B" Brodie in my collection is definitely magnetic steel.  All other Brodie shells including the Examples of the "War Office Pattern" are non-magnetic but the rims, where fitted, are magnetic.  My understanding is that the requirement was that helmets should pass the ballistic test, etc. and I can trace no War Department requirement that helmet shells should be made from magnetic or non-magnetic steel. However, if anyone has information in this respect I shall be very pleased to hear. 

 

My opinion, for which I have no authority, is that the magnetic shells encountered were manufactured from steel supplied by the U.S.A.   This makes sense as the American Model 1917 helmets in my collection are all magnetic.

 

Peregrinvs,

 

The "Type A" helmet measured 295mm from side to side and 317mm from front to rear.  The brim measured 40mm at front and rear and 50mm at each side.  The Type "B" measured 262mm from side to side and 288mm from front to rear.  The brim was 35mm on one side and 32mm on the other and 25mm at the front and 29mm at the rear.  The measurements given are not necessarily to be relied upon as they varied by up to 3mm on different examples particularly on the Type "B" and it goes without saying that not many examples were available.  

 

Regards,

 

Michael.

Michael

 

I am very glad I found your post. When you mentioned that the U.S.A ww1 helmets or m 1917 you own are magnetic I immediatly could relate. I have read 2 or 3 websites that said that the U.S helmets were also non magnetic. But I knew mine was original because my heat stamp said YJ 148 and from my understanding the YJ stamps mean they are American made for ww1. They are just less common than the Z stamp. I could also tell I had a sawdust finish which is original. But when a magnet stuck to it I was confused thinking maybe it was just the YJ stamped helmets that were magnetic. So thank you for some clarification. Some U.S helmets are definently magnetic. 

 

Thanks,

Dylan

[JMB1943]

The lower photo in post #22 from Peregrinus shows the remnant of a white, woven material surrounding the suspension rivet.

 

Is that part of the asbestos pad that was fitted to Brodie helmets ?

 

Regards,

JMB